Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 ca4219ba92856ec0…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:45:35 Authoring application: Microsoft Excel First seen: 2021-10-23
MD5: 9fd21919737d88384676ffb65efca7ff SHA-1: 29b5e001414f68ab8f6038b292ae7b0cab39e1be SHA-256: ca4219ba92856ec0c48dcb5131509911a6c07d13ea124c0dba255af5f79ceab1
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file is an Excel 4.0 macro-enabled workbook containing an Auto_Open function, which is a common technique for executing malicious code upon opening. The critical heuristic firings indicate the presence of dangerous formula APIs within the Auto_Open macro, suggesting an attempt to exploit vulnerabilities or download further payloads. No specific family could be identified, but the technique is indicative of a macro-based malware delivery.

Heuristics 3

  • Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME
    oletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN
    Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6807 bytes
SHA-256: 76602b1e49cdbba863c119c8d5dfc17346a68abd40bbd830fa6e066564f0c9e3
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     18 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  JIJfmImMx
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!H183 
' 0018     22 LABEL : Cell Value, String Constant - BQmQlHf len=0 
' 0018     22 LABEL : Cell Value, String Constant - CEaiGiF len=0 
' 0018     24 LABEL : Cell Value, String Constant - fVqtPJzCD len=0 
' 0018     26 LABEL : Cell Value, String Constant - GfLJukZiFDs len=0 
' 0018     20 LABEL : Cell Value, String Constant - GODQZ len=0 
' 0018     21 LABEL : Cell Value, String Constant - GyQLVS len=0 
' 0018     26 LABEL : Cell Value, String Constant - iciVfVrjjht len=0 
' 0018     24 LABEL : Cell Value, String Constant - kGCjAPgXI len=0 
' 0018     22 LABEL : Cell Value, String Constant - MbJAWVM len=0 
' 0018     22 LABEL : Cell Value, String Constant - npUwhMB len=0 
' 0018     20 LABEL : Cell Value, String Constant - OOdVn len=0 
' 0018     23 LABEL : Cell Value, String Constant - PEhZsjmQ len=0 
' 0018     25 LABEL : Cell Value, String Constant - qBLNkzhDbe len=0 
' 0018     21 LABEL : Cell Value, String Constant - QZmTpA len=0 
' 0018     20 LABEL : Cell Value, String Constant - rDCcT len=0 
' 0018     22 LABEL : Cell Value, String Constant - slkmPLi len=0 
' 0018     24 LABEL : Cell Value, String Constant - TvVbCMYSH len=0 
' 0018     25 LABEL : Cell Value, String Constant - vLnAKIrgpy len=0 
' 0018     23 LABEL : Cell Value, String Constant - YULKuDrV len=0 
' 0018     20 LABEL : Cell Value, String Constant - zJqkB len=0 
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : 
... (truncated)

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